Catheters for insertion through a blood vessel in the heart, and other catheters as well, are in very common medical use. When such a catheter is inserted into a blood vessel, it has to follow the irregularly shaped path defined by the blood vessel until the distal end of the catheter reaches the desired location in the heart or elsewhere.
To assist in this purpose, some catheters have been previously formed with a curved distal end. A guide wire may be inserted into the bore or lumen of the catheter, thereby straightening out the preformed curve. For example, the guide wire may be positioned to reduce the curve of the distal end of the catheter when placing the catheter into the atrium of the heart. However, some curvature is required to allow passage of the catheter through the heart valve, and this can be provided in prior art catheters by retraction of the guide wire. For known suction/ablation catheters, location of a desired conduction pathway in the heart is generally accomplished as well while the catheter is in its curved configuration with the guide wire retracted or removed. If the prior art catheters need to be straightened at their distal ends again, the guide wire may be once again advanced.
There is a present need for greater freedom of motion of catheter tips in some medical procedures, above and beyond that which can be currently provided in catheters having preformed tips at their distal ends, which tips may be straightened out by means of a guide wire. For example, in suction/ablation catheters, when one is mapping the conduction pathways or site of origin of abnormal electrical activity in the heart, greater flexibility of the curved, preformed tips of prior art catheters would be desired. At the present time, manipulation of the guide wire is often necessary to permit the curve to assume its shape and then to straighten it out again as the mapping takes place. However, it may be desired for the curved tip to assume a different shape than the curve that is preformed into a prior art catheter, with a curve that is either greater or lesser than the preformed curve, but not straight.
In accordance with this invention, a catheter is provided in which the physician-user can manipulate the curvature of its distal end, in a single plane, over a predetermined arc of variable positions. Such a catheter, for example, could be used for locating, mapping, and ablating abnormal conduction tissue in the heart with less manipulation and more assurance of good performance. It also may be used with advantage for many other purposes.
Additionally, the catheter of this invention more easily follows the contours of the ventricle of the heart, for example, for better positioning of an electrode for desired ablation of a portion of cardiac muscle containing an abnormal conduction pathway. The improved variable curvature of the distal end of a catheter of this invention facilitates this purpose, and also any of the large variety of medical or any other desired procedures involving a catheter or a structural equivalent thereto.